I haven't really ruled out the EM5, I just hadn't really considered it (if that makes sense...). I think part of what I'm looking for in this camera is a slightly different 'picture-taking' experience, and in my head (swirling around with all the other crap) is the thought that I don't want a camera that looks like a dslr - eg. Sony A7, Olympus EM1, EM5 etc. All of this may change as I keep looking at different cameras and thinking about what I really want to do with it (as opposed to using the 1dx system). I'm not in a rush, so I will definitely try as many options as I can.
Realistically, there are so many cameras/lenses available that can give fantastic results in the right hands, that for me it comes down to how I feel about using a particular camera. As we all know, on web forums you can find enough people who love or hate any particular camera, either the files that it produces or the way it handles or operates, so it often distills to how the photographer relates to the camera.
Jim made the analogy to bicycles (of which I share the passion) and more often than not, it's how a particular bike makes you feel - it may be how it handles, the colour, the stickers - the important thing is when you look at it, it makes you want to jump on and go for a ride.